For manufacturing of a laminated tube of large diameter, such as 25 mm and beyond, the stiffness or the body strength of the laminated tube becomes an important attribute. In general, laminate of thickness of about 250μ a and higher are typically used for manufacturing tubes of larger diameter.
Usual polymer combinations used for making such laminated tubes are selected from Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE), High Density Polyethylene (HDPE), Ethylene Vinyl Alcohol (EVOH) etc. In some manufacturing processes, Polypropylene (PP) is also used as a one of the polymers.
Polypropylene being an inert polymer is very difficult to bond with other poly ethylene film substrates. Moreover, Polypropylene requires comparatively high temperature to seal with each other. HDPE polymer, on the other hand, is easier to process singularly or in combination with other low and medium density Polyethylene. HDPE polymers based film could be manufactured by co-extruded Cast or co-extruded blown. Pure High Density Polyethylene film and laminate is known to have poor Environmental Stress Crack Resistance (ESCR) and poor Impact resistance.